This is extremely difficult. Essentially this is normally a situation where parked vehicles have narrowed the road to one lane and there is oncoming traffic, or where there is a priority sign, width restriction or any situation where there is a fifty-fifty decision when you deal with other traffic. What makes things so difficult is that you have to second-guess what other road users are going to do. Good forward planning will help make better judgements as you have longer to think and reach a good decision. You must not wave to, flash at or gesticulate to other road users as this contravenes the Highway Code.